Pencil soldering iron



Sept. 24, 1963 T. E. FlNcH PENCIL soLDERINq IRON Filed Feb. 2'?,V 1962 2 Sheets-Sheet 1 INVENTOR. THOMAS E. FNCH BY mmf 7/ @if ATTORNEY Sept. 24, 1963 T. E. FlNcH PENCIL soLDERING IRON Filed Feb. 27', 1962 INVENTOR. THOMAS E. FINCH A//A/A I 2 Sheets-Sheet 2 ATTORNEY 3,165,135 PENCIL SLDERING IRUN Thomas E. Finch, Shelbyville, ind., assignor to General Electric Company, a corporation or New York Filed Feb. 27, 1962, Ser. No. 175,989 s claims. (ci. 21a- 26) This invention relates primarily to electrically powered hand tools, and more particularly to an 'arrangement for electrically connecting and mechanically locking an electrically powered tool in its supporting handle.

In electrically powered tools, such as soldering irons,

the tool tip is subjected to wear or damage and frequently needs to be removed for cleaning or replacement, or for the substitution of a dilferent type tip. It is therefore the main object of this invention to provide a construction for electrically connecting and mechanically supporting a removable electrically powered tool so the tool is positively locked in place in its handle and its removal and replacement can be made quickly without the use of auxiliary tools.

A further object of this invention is to provide asimple, reliable and relatively inexpensive connecting device having improved electrical and mechanical characteristics and which minimizes lthe 4heat tnansfer to the handle.

Another object of this invention is the provision of an improved support for a removable electrically powered work tool in which electrically energized metal parts are shielded to minimize the possibility of electrical hazards to the operator if the tool is removed while energized.

Briey stated, in accordance with one aspect of my invention, I provide a molded connector assembly formed of an insulating material and incorporating a resilient leaf spring having a detent on its free end to engage a shoulder on the tool to lock the tool securely to t-he connector assembly.

Further objects and advantages will become apparent and the invention will be better understood from the following description and the accompanying drawings. The features of novelty which characterize this invention are set forth in the claims attached to and forming part of this specication.

In the drawings:

FIG. 1 is a side elevation view, partly in cross-section, of the connector assembly of this invention as applied to a soldering iron prior to its assembly into the handle.

FIG. 2 is an enlarged top cross-sectional view of the connector assembly of FIG. 1.

FIG. 3 is a cross-sectional view taken along lines 3-3 of FIG. 2.

FIG. 4 is a cross-sectional view taken along lines 4 4 of FIG. 2.

FlG. 5 is a cross-sectional view taken along lines 5 5 of FIG. 2.

FIG. 6 is a cross-sectional view taken along lines 6-6 of FIG. 2.

FIG. 7 is a cross-sectional view taken along lines 7 7 of FIG. 2.

As shown in the drawings, the soldering iron 141 comprises la conventional sheathed heater 11 having a centrally located heating element (not shown), the ends of which are connected to a pair of terminals 12, and an external metallicsheath spaced from the heating element by an insulating material such las magnesium oxide or another refractory material. A soldering iron tip, not shown, may be secured to the sheath of the heater 11 in any suitable manner to provide efficient heat transfer therebetween. When electrical power is applied between the terminals 12 of the heating element, electrical current will llow through the heater element to heat the soldering iron tip.

Referring more particularly to FIG. 1, there is shown the connector assembly of this invention wherein an integral molded connector device 22 formed of an insulating material, such as nylon, is molded to the shape most clearly illustrated by FIGS. 2, 3, 4, 5, 6 and 7.

A handle 16, which is formed of an insulating material such as a plastic or wood, has a small bore 24 to slideably receive the power cord 14 and is also provided with an enlarged bore 23 to receive the connector device 2.2.

As shown in FIG. l, the outside diameter of connector device 22 is slightly smaller than the inside diameter of the bore 23 of the handle 16. One end portion of the connector device 22 is, las shown in FIG. 3, in the form of a round tube having Ilongitudinal guide ridges 26 formed on the inner surface thereof and a longitudinal slot 25 for receiving the detent 4d of the locking spring y13, as indicated in FIG. 1.

As shown in FIG. 2, the connector device 22 is provided with a pair of parallel apertures or channels 28 and 29, which receive the curved contact portions Zlib and 2lb of the power contacts l2@ 'and 21, respectively. Power contacts 2t? and 21 are formed of a resilient conducting material such as berylium copper or spring bronze. Channels 28 and 29 are, as indicated in FIG. 4, shaped to receive the terminals 12 of sheathed heater 11. As best shown in FIG. 6, the opposite end of connector device 22 is provided with a pair of longitudinal chambers 33 and 34 separated by a central divider 27 to electrically isolate the bare ends of the conductors 1S and 19 of the power cord 14 from each other. As will be apparent, the ends of conductors 13 and 19 are connected to the power contacts 20 and 21 by solder joints 35 and 36.

It further will be observed Iin FIG. 2 that the peripheral walls of chambers 33 and 34 extend a substantial distance beyond solder joints 35 and 36 to provide a shield for the bare ends of the conductors 18 and 19, to eliminate the possibility of a shock hazard in the event that an operator disassembles the soldering iron with which it is energized.

The connector device 22 is further provided with a pair of backwardly extending tabs 37 and 3S, as best shown in FIG. 7, which are attached to power cord 14 by oval clamp 15 to positively position the power cord 14 longitudinally with respect to the connector device 22, and to relieve any stress on the soldered connections.

As further apparent from FIGS. 4-7, a longitudinal spring groove 30 is provided on the outer periphery of connector device 22. Groove 3b is aligned with slot 25 of the connector device 22.

To assemble the soldering iron, the power cord 14 is inserted through bores 24 and 23` of the handle 16. Power contacts 20 and 21 are then soldered to conductors 18 and 19 at 35 and 36 respectively. Power contacts 20 and 21 are then longitudinally inserted into the chambers 33 and 34, and channels 28 and 29 of connector device 22.

It will be observed in FIG. 2 that spring tabs 20a and 21a provided on power contacts 20 and 21, respectively, engage shoulders 31 and 32 of channels 28 and 29. It will further be noted that the power contacts Ztl and 21 =are enlarged at one end, as best shown in FIG. l, to provide shoulders 4l and `42, which bottom in chambers 33` and 64 of connector device 22, to cooperate with the tabs 20a and 21a to position and lock power contacts Ztl and 21 in their assembled positions.

With the power cord 14 and power contacts Ztl and 21 thus assembled with connector device 22, the locking spring 13 is positioned in groove 3l) of connector device 22 and -secured to the power cord 14 and the tabs 37 and 3S of connector device 22 by an oval clamp 15. Locking spring 13 is notched `as indicated at 43. Thus, when the notch 43 is clamped by oval clamp 15 in alignment with grooves 39 and 411 of tabs 37 and 38, a predetermined E longitudinal dimensional relationship between the locking spring 1'3 and the connector device 22 is obtained.

As shown in FIG. l, a ground wire 17 may be inserted in a preformed hole in locking spring 13 and electrically soldered thereto as indicated at 44. As will be readily apparent, this ground connection will provide an electrical ground for the sheath of the heater 11 which engages the idetent or locking tab 48 of the llocking spring 13.

The -terminal end 45 of sheated heater 11 is enlarged to provide ya shoulder 49 adjacent its terminals 12. The diameter of the enlarged terminal end 45 is approximately the same as the inner diameter of the tubular end of connector device 22 to provide mechanical supporty for the tool when assembled. The enlarged end 45 of the sheathed heater 11 is further provided with a pair of grooves 46 which engage ridges 26 of the connector device 22 for alignment of the terminals 12 with channels 28 and 29 and power contacts 20 and 21 to prevent the twisting of the tip after assembly in the handle 16.

With the enlarged terminal end 45 of the sheathed heater 11 bottomed in the tubular end of connector device 22 and handle 16 positioned as shown by the solid lines of FIG. 1, the iinal assembly is accomplished by sliding the handle 16 longitudinally to the position shown by the dotted line of FIG. 1. -It will be observed that in this assembled position the locking spring 13 is positioned in spring groove 30 of connecting device 22 and is ilattened from its relaxed position, as shown inthe solid Vlines of FIG. l, so that the locking tab 4S of the locking spring 13 assumes the position shown in dotted lines in which it engages the shoulder `49 of the sheathed'heater 11. Thus the locking tab 48 positively locks the soldering tool in place. 'The spring pressure of locking spring 13 against the inside'surface of the bore 23` of handle 16i also causes the connector device 22 to engage the surface of the bore 23 of the handle 16 with a friction fit to retain the soldering iron and its handle in the assembled position. Y It will be observed that the end 50 of locking spring 13 will engage the bottom 51 of the bore 23 of the handle 16 to longitudinally position the handle 16 at its preselected Iassembled position. It will also be observed that the entire length Vof the sheathed heater 11, other than the enlarged terminal portion 4S, is exposed to the atmosphere outside of the handle 16. The construction minimizes the amount of heat transferred to the handle.

Although I have shown and described a particular embodiment of my invention in connection with a soldering iron, it will be understood by those skilled in the art that my invention may yalso be used in connection with other types `of electrical hand tools. Moreover, modifications of my invention will occur to those skilled in the art. lt should be understood, therefore, that my invention is not limited'to the particular arrangement shown, and IV intend in the appended claims to cover all modifications which do not depart from the spirit and scope of this invention.

What I claim as new and desire to secure by Letters p Patent of the United States is:

heaterv comprising a connector device apertured to receive the heater terminals, and a leaf spring extending engagement with the shoulder on the heater upon insertion of the connector device with the heater assembled thereto into the bore of said handle, the inner surface of said bore firmly engaging said leaf spring and holding it against radial movement of suflcient magnitude to disengage said detenrt from said shoulder, the assembly of said connector device and said heater being arranged for axial movement within said bore against the frictional force caused by the engagement of said spring with the inner surface of said bore, whereby the assembly of the heater and the connector device must be moved axially to disengage said leaf spring from restraining engagement with said bore to release said detent before the heater can be disassembled from the connector device.

2. An electric soldering iron as set forth in claim 1 wherein the connector device is provided with a pair of axially disposed portions extending in the direction remotel from the heater, said axially disposed portions being clamped to a power cord and said leaf spring for longitudinally positioning the detent of the spring axially with respect to said connector device.

3. An electric soldering iron as set forth in claim 2 in which the axially disposed portions of the connector device and the leaf spring yare provided with aligned notches in which the clamp is positioned.

4. An electric soldering iron as set forth in claim 1 in which the connector device includes a sleeve portion which surrounds the terminal end of the heater to provide mechanical support for the heater.

5. An electric soldering iron as set forth in claim 4 wherein the sleeve portion `and the heater are provided with complementary grooves and ridges which engage each other to prevent the twisting fof the heater with repect to the connector device. f6. An electric tool comprising a handle having a hollow bore, a removable electrically powered device having a pair of centrally located power terminals projecting from one end thereof, means providing a shoulder on the outer surface of said device adjacent said power terminals, means for supporting the device in the handle and for conducting electrical power to the device comprising a molded connector having channels containing power contact elements and for receiving the power terminals of the device, and a spring member secured to the molded connector device, said spring member having a free end provided with a locking tab and being rmly engaged by the inner surface vof said hollow bore so as to be urged into engagement with said shoulder to lock the device in its assembled position, the assembly of said supporting means and said removable device being arranged for axial movement within said hollow bore against the trictional force caused by the engagement of said spring member with the inner surface of said bore, whereby the assembly of said removable device and said supporting means must be moved axially to disengage said spring member from restraining engagement with said bore to release said locking tab before said device can be disassembled from said supporting means.

Referent-es esta in the are of thisY patent UNITED STATES PATENTS 2,246,719 Burnham June 24, 1941 V2,476,762 Petre et al. July 19, 1949 2,488,477 Rapap'ort Nov. 15, 1949 2,544,326 Jones, l 4 Mar. 6, 1951 2,596,594 Petre l May 13, 1952 2,619,576 Greibach Nov. 25, 1952 2,717,952 y Dvorak Sept. 13, 1955 3,023,295 Johnson Feb. 27, 1962 

1. AN ELECTRIC SOLDERING IRON COMPRISING A HANDLE HAVING A HOLLOW BORE, A SHEATHED ELECTRICAL HEATER HAVING A PAIR OF TERMINALS PROJECTING FROM ONE END THEREOF, MEANS PROVIDING A SHOULDER ON THE SHEATH OF SAID HEATER ADJACENT SAID TERMINALS, MEANS FOR SUPPORTING THE HEATER IN THE HANDLE AND FOR CONDUCTING ELECTRICAL POWER TO THE HEATER COMPRISING A CONNECTOR DEVICE APERTURED TO RECEIVE THE HEATER TERMINALS, AND A LEAF SPRING EXTENDING AXIALLY ALONG THE OUTER SURFACE OF THE CONNECTOR DEVICE AND HAVING A DETENT AT ITS FREE END WHICH IS URGED INTO ENGAGEMENT WITH THE SHOULDER ON THE HEATER UPON INSERTION OF THE CONNECTOR DEVICE WITH THE HEATER ASSEMBLED THERETO INTO THE BORE OF SAID HANDLE, THE INNER SURFACE OF SAID BORE FIRMLY ENGAGING SAID LEAF SPRING AND HOLDING IT AGAINST RADIAL MOVEMENT OF SUFFICIENT MAGNITUDE TO DISENGAGE SAID DETENT FROM SAID SHOULDER, THE ASSEMBLY OF SAID CONNECTOR DEVICE AND SAID HEATER BEING ARRANGED FOR AXIAL MOVEMENT WITHIN SAID BORE AGAINST THE FRICTIONAL FORCE CAUSED BY THE ENGAGEMENT OF SAID SPRING WITH THE INNER SURFACE OF SAID BORE, WHEREBY THE ASSEMBLY OF THE HEATER AND THE CONNECTOR DEVICE MUST BE MOVED AXIALLY TO DISENGAGE SAID LEAF SPRING FROM RESTRAINING ENGAGEMENT WITH SAID BORE TO RELEASE SAID DETENT BEFORE THE HEATER CAN BE DISASSEMBLED FROM THE CONNECTOR DEVICE. 